Hydraulic apparatus



2 Sheets-Sheet 1 Mw. S. f f J f s DE@ s ii: Ea n E L nm F. J. WRIGHTHYDRAULIC APPARATUS Aug. 2, 1955 Original Filed June 19. 19415 Z2/i 1 fIr ATTORNEY Aug- 2, 1955 F. J. WRIGHT HYDRAULIC APPARATUS 2 Sheets-Sheet2 Original Filed June 19, 1943 INVENTOR FRED .LWRIGHT BY WM 12v/MwahATTORNEJ/ Reiasued Aug. 2, 1955 HYDRAULIC APPARATUS Fred J. Wright,Columbus, Ohio, assignor to The Denison Engineering Company, Columbus,Ohio, a corporation of Ohio Original No. 2,480,069, dated August 23,1949, Serial No. 491,498, .lune 19, 1943. Application-for reissue August22, 1950, Serial No. 180,781

9 Claims. (Cl. 10S-162) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specilication; matterprinted in italics indicates the additions made by reissue.

The present invention relates to iiuid pressure energy translatingdevices such as hydraulic motors and pumps and more particularly tomotors and pumps employing a cylinder barrel, reciprocating pistonstherein and an associated angularly disposed thrust plate or ring which,when relative rotation is imparted between the elements of the motor orpump, causes reciprocation of the pistons.

One of the objects of the present invention is t provide a translatingdevice of the above mentioned type in which the driving connection,between the barrel and shaft. is disposed so that the resultant forcesof thrusts, created by the association of the pistons with the thrustring, pass from the barrel to the shaft at the connection.

In translating devices of the type above mentioned, a shaft is employedfor driving the barrel when the device functions as a pump or the shaftis driven by the barrel when the device functions as a motor. A drivingconnection, such as a spline, is interposed between the barrel andshaft.

Another object of the present invention is to provide a hydraulic pump,or motor, comprising a barrel having one or more cylinders formedtherein, and pistons in the cylinders, the pistons being forcedoutwardly against piston actuating mechanism by a spring, which springreacts against the barrel for urging the barrel into frictionalengagement with a member having ports for supplying liquid to anddirecting the liquid from the cylinders.

Another object of the invention is to provide a coil spring for reactingbetween the cylinder barrel of a pump. or motor, and the piston in acylinder of the cylinder barrel, which spring is mounted at one end 0n afriction reducing bearing.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodiment of the invention isclearly shown.

In the drawings:

Fig. 1 is a view, partly in section, of a hydraulic pump embodying theinvention;

Fig. 2 is a perspective View of a spring support member;

Fig. 3 is an end view of the cylinder barrel as viewed on the line 3-3of Fig. l;

Fig. 4 is an end view of the port plate as viewed on line 4 4 of Fig. l;

Fig. 5 is a view similar to Fig. l but illustrates more clearly one ofthe features of the invention; and

Fig. 6 is a diagrammatic view showing the relation of the cylinderbarrel and pistons to the thrust ring and the forces acting on theseelements during the operation of the device.

Although the present invention is directed broadly to fluid pressureenergy translating devices such as fluid motors or fluid pumps, I haveshown the same as a hydraulic pump merely for the purpose ofillustrating one embodiment of the invention.

Referring to the drawings, I have shown a hydraulic pump comprising ahousing 2l formed by cylindrical housing sections 22 and 23 joinedtogether by bolts 24.

One end of the section 23 is closed by a cap or port plate 26, whichplate is attached to the housing by bolts 27. A drive shaft 30 isjournaled at one end in a bearing 31 in the plate 26 and adjacent theother end by a bearing 32, which bearing is in the housing section 22.The shaft 30 is splined at 34 and a barrel 35 is keyed to the shaft 30by the splines 34. The barrel 35 is disposed in housing member 23 and isprovided with a plurality of cylinders, one of which is shown in Fig. 1at 36, which cylinders extend parallel with the axis of the barrel andare spaced equally from one another about the barrel and at equaldistance from the axis of the barrel. Each of the cylinders 36 has aport 37 leading from the end face 38 of the barrel 35 to the cylinderthrough which liquid is taken into and discharged from the cylinder. Theface 38 of the barrel is maintained in frictional engagement with theface 39 of the port plate 26 as will be more fully explainedhereinafter.

A cylindrically shaped piston 40 is prt-vided for each cylinder, whichpiston is closed at 4l, the opposite end being open. The outer end 41 ofthe pistons 40 are shaped spheroidally, the purpose of which will appearhereinafter. Coil springs, one of which is shown at 44,

are disposed within the pistons 40, an end of each spring abuts theclosed end 41 of a piston and the opposite end being supported by freelyrotatable bearings 45. The bearings 45, only one being shown, eachcomprise an open end spring retainer support 46 disposed in a cylinder36 and having three openings 47 n the sides and a spindle 48 extendingfrom the closed end thereof. The open end of the support 46 abuts theend of the cylinder 36 and surrounds the port 37. The openings 47 formpassages through which the liquid passes to and from the cylinders. Aspring retainer in the form of a thimble 49 is rotatably supported onthe spindle, and the spring 44 abuts a peripheral tiange 50 of thethimble 49. The end of the spindle 48 is spheroidally [spheroidically]shaped and the side walls and end are highly polished; likewise theinside of the thimble 59 is highly polished so that the thimble 49rotates freely on the spindle. Since the liquid handled by the pump isoil, the bearing is well lubricated.

A cylindrically [cylindrical] thrust plate 52 is rotatably supported byand within the housing section 22 by a ball bearing 53. The plate 52 issupported so that the axis thereof is tilted with respect to the axis ofthe cylinder barrel 35. The pistons 40 are biased outwardly and intoengagement with the face 54 of the plate 52. It is apparent that whenthe drive shaft 30 is rotated, the cylinder barrel 35 will be rotatedand the springs 44, together with the camming eiect of the plate 52,will cause the pistons 40 to be reciprocated in the cylinders The endcap or port plate 26 is provided with arcuate oil inlet and outlet ports55 and 56 in the face 39 thereof, and the ports 37 of the cylinders 36progressively register, first with one of these ports and then the otheras the barrel 3S rotates so that oil is drawn into the cylinders 36 asthe pistons 40 move outwardly, and, as the pistons are moved inwardly,the oil in the cylinders 36 is forced out through the other arcuateport. The ports are connected with conduits, not shown, for directingthe oil to and from the pump.

It will be apparent from the foregoing description, and the drawings,that the cylinder barrel 35 is contained within and is whollyunsupported by the casing or housing except through the port plate 26and that shaft 30 which extends through the central axial opening in thecylinder barrel is spaced substantially from the walls of this centralopening throughout the larger portion of the length of the latter. Also,as clearly shown in the drawings, the cylinder barrel 35 is whollyunsupported by the shaft 30 except at that end of it which is remotefrom the port plate 26 and at said end it is connected to the shaft 30through a motion permitting spline connector means. As clearly indicatedin the drawings, this motion connector means includes straight splineswhich extend axially along the shaft 30 and spline means carried by thecylinder barrel which interfit with the spline means on the shaft 30 toprovide the slidable connection above referred to. It will be apparentthat by following ordinary machine shop practices in forming the splinesof both the cylinder barrel and the shaft so that they will be slidableone on the other that a slidable motion permitting connector between thecylinder barrel and shaft will be provided which will also permit asmall amount of bending or bowing of the shaft 30 between the bearings31 and 32 without causing the cylinder barrel 35 to become locked totheshaft 30 when the latter is under loads sufficient to bend or bow theshaft. This is another important feature of the invention since it hasbeen found in practice where the cylinder barrel and shaft do becomelocked as above described, that the bending of the shaft will causeseparation of the cylinder barrel and port plate. It will be apparentthat the length of the cooperating surfaces of the spline connectionbetween the cylinder barrel and \haft should be of as short a length asfeasible to permit bending or bowing of the shaft without causing theseal between the cylinder barrel and port plate to become broken andthat as indicated in Figs. I and 5 of the drawings, it is preferred thatthe length of the contacting portions of the splines on the cylinderbarrel and shaft be less than one-third the overall length of thecylinder barrel.

Since the cylinder barrel 35 is capable of longitudinal movement on thedrive shaft 24, it is necessary to cause the barrel to be urged againstthe face 39 of the port plate 26 during starting of the pump for sealingthe passages between the arcuate ports of the port plate and the portsof the cylinders. By abutting one end of the springs 44 with thecylinder barrel 35 and the opposite ends of the springs with the pistons30. the springs provide a reacting force between the plate S2 and thebarrel for urging the barrel against the face 39. After the pistons havecommenced to pump oil, the pressure of the oil against the port end ofthc cylinders urges thc barrcl 35 into Contact with the face 39 of theport plate.

By forming the ends 31 of the pistons 4I] sphcroidally. a minimum ofarea of the piston will engage the plate 52 thereby minimizing friction.It is apparent that the ends of the pistons will engage the face 54 ofthe plate 52 at one side of the axes [axis] of the pistons and when thebarrel 35 rotates. the pistons will be rotated about their axes. Sincethe springs 44 connect directly with the pistons 40. although merely byfriction, the springs will have a tendency to rotate about their axiswith the pistons. By supporting the opposite ends of the springs by abearing which is freely rotatable, the springs will rotate with thepistons and are, therefore, not subject to an appreciable torsionalstrain, and there is no frictional sliding between the pistons andsprings. This lengthens the effective life of the springs and preventswearing on the inside of the pistons.

Referring particularly to Fig. 6, it will be seen that the splineconnection 34, between the shaft 3l) and barrel 36, is disposed wherethe resultant of the components of the thrusts, created by therelationship of the pistons 40 and thc thrust plate 52, is transferredfrom the barrel to the shaft. This is apparent since there are twocomponents of force acting on each piston, these being indicated bylines A" and B. The resultant force on Cab elch piston is indicated by aline C." The length of line B is determined by the center of the radiusfor the spheroidical end 4l of the piston. These centers are indicatedby D. The starting points or nucleuses ol the resultant forces fallwithin a plane D. 'Ihctefore, the seven resultant forces indicated bythe lines C" of the component forces A and B," fall axially within thecontines of the spline connection 34.

By arranging the spline as herein disclosed, the rcsultant forcestransmitted between the barrel and shaft are all substantiallydownwardly, as viewed in Fig. 6, with the result that the resultantforce urging the face of the barrel against the face of the port plateis substantially parallel with the axis of the barrel, that is, theresultant force, created by the association of the pistons with thethrust ring, is substantially at right angles to the engaging faces ofthe barrel and port plate. Consequently, torsional strain at these facesis reduced to a minimum. Moreover the thrust between the thrust ring andthe piston is at right angles to the ring and thereby wear on the endsof the pistons, the thrust ring and the bearings for the latter isreduced to a minimum.

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

I claim:

l. A huid pressure energy translating device comprising a cylinderbarrel having a plurality of piston chambers with ports adjacent one endthereof; pistons dis posed in said chambers, said pistons comprisingcylindrical members closed at one end and open at the opposite end, saidopen ends facing toward the ends of the chamber provided with said ports[parts]; coil springs having one end thereof extending into said pistonsand connected therewith; bearing members comprising base elementsabutting said ported ends of said chambers, said base elements beingopen for the passage of fluid therearound; and means forming rotatableconnections between said base elements and said springs.

2. A huid pressure energy translating device comprising a cylinderbarrel having a plurality of piston chambers with ports adjacent theinner ends thereof; pistons slidably mounted in said chambers, saidpistons. being hollow and having closed cnds projecting from saidchambers; tapered coil springs disposed within said pistons; means atthe closed ends of said pistons for locating the small end of thesprings in spaced relation from the side walls of said pistons; bearingmembers abutting the ported ends of said chambers, said bearing membersbeing open for the passage of uid therethrough, and means on saidbearing members for rotatably supporting the other ends of said springsin spaced relation from the walls of said pistons.

3. A liuid pressure energy translating device comprising a cylinderbarrel having a plurality of piston chambers with ports adjacent theinner ends thereof; pistons slidably mounted in said cylinders, saidpistons being hollow and having closed ends projecting from saidchambers; tapered coil springs disposed in said chambers; means forpreventing the engagement between said springs and the side walls ofsaid pistons, said means having base elements disposed at one end ofsaid chambers; means on said base elements for rotatably supporting andlocating one end of said springs; and, means frictionally engaging thesprings at the opposite ends of the chambers for holding the springsaway from the piston side walls.

4. A fluid pressure energy translating device comprising a cylinderbarrel having a plurality of piston chambers with ports adjacent theinner ends thereof; pistons slidably mounted in said cylinders, saidpistons being hollow and having closed ends projecting from saidchambers; tapered coil springs disposed in said chambers; means forpreventing the engagement between said springs and the side walls ofsaid pistons, said means having sockets provided at one end of thechambers to receive the small ends of said springs; and, base membersdisposed at the opposite ends of said chambers, said base members havingbearing and spring receiving and centering devices rotatably supportedon said bearings.

[5. In a uid motor, a casing; a port plate in said casing; a cylinderbarrel disposed with one end wall in sliding engagement with said portplate, the remaining walls being spaced from the walls of said casing,said cylinder barrel having a central opening and cylinders parallelwith and spaced from said opening; piston means disposed forreciprocation in said cylinders, said pistons having spheroidally shapedends the centers of generation of which are disposed in the axialcenters of said pistons; an inclined thrust member disposed inengagement with said ends of said pistons; a shaft extending into thecentral opening in said cylinder barrel; and a splined drivingconnection between said shaft and said cylinder barrel, said connectionextending a limited distance on either side of a plane passing throughthe centers of generation of the. spheroidal ends of said pistons] [6.ln a ud motor, a casing; a port plate in said casing; a cylinder barreldisposed with one end wall in sliding engagement with said port plate,the remaining walls thereof being spaced from the walls of said casing,said cylinder barrel having an axial opening and cylinders parallel withthe longitudinal axis thereof; piston means disposed for reciprocationin said cylinders and projecting from the end of said cylinder barrelopposite that engaging said port plate; the outer ends of said pistonsbeing spheroidally-shaped and having the centers of generation thereofin the axial centers of said pistons and near the adjacent end of saidcylinder barrel; an inclined thrust member disposed in engagement withsaid ends of said pistons; a shaft extending into the axial opening insaid cylinder barrel; and a loose splined driving connection betweensaid shaft and said cylinder barrel, said connection being locatedadjacent the end of said cylinder barrel from which said pistonsproject] 7. A fluid pressure energy translating device including meansforming a casing; port plate means in said casing; a cylinder barreldisposed in said casing, said cylinder barrel having outer walls andopposite ends, one of said ends being in sliding engagement with saidport plate means, said cylinder barrel otherwise being at all times outof engagement with and unsupported by said casing, means in saidcylinder barrel forming a central opening extending axially therein andabout the axis of which said cylinder barrel rotates, and a plurality ofcylinders spaced around said central opening on axes extending generallyparallel to the axis of said central opening; pistons disposed forreciprocation in said cylinders, said pistons having spheroidally shapedends the centers of generation of which are disposed on the axialcenters of said pistons and cylinders; an inclined thrust member in saidcasing disposed in engagement with the spheroidally shaped ends of saidpistons,` a shaft extending in said central opening the outer surface ofwhich is spaced substantially from the inner surfaces of said cylinderbarrel opening throughout the major portion of the axial length of thelatter; antfriction bearing means in said housing at opposite ends ofsaid cylinder barrel carrying said shaft for rotation; and a motionpermitting connector means interconnecting said cylinder barrel andshaft including means forming a plurality of splines carried by saidcylinder barrel and extending in the central opening thereof fromadjacent the end thereof remote from said port plate means for adistance of less than one-third the total length of said cylinderbarrel, and means on said shaft forming a plurality of circumferentiallyspaced straight splines extending axially of said shaft and interfittingwith said splines carried by said cylinder barrel and being of greaterlength than the latter, said splines carried by said cylinder barrelhaving a length such that they extend a limited distance on each lilside of a plane passing through the centers of generation of thespheroidally shaped ends of said pistons.

8. A fluid pressure energy translating device including means forming acasing; port plate means in said casing; a cylinder barrel disposed insaid casing, said cylinder barrel having outer walls and opposite ends,one of said ends being in sliding engagement with said port plate means,said cylinder barrel otherwise being at all times out of engagement withand unsupported by said casing, means in said cylinder barrel forming acentral opening extendingI axially therein and about the axis of whichsaid cylinder barrel rotates, and a plurality of cylinders spaced aroundsaid central opening on axes extending generally parallel to the axis ofsaid central opening; pistons disposed for reciprocation in saidcylinders, said pistons having spheroidally shaped ends the centers ofgeneration of which are disposed on the axial centers of said pistonsand cylinders; an inclined thrust member in said casing disposed inengagement with the spheroidally shaped ends of said pistons; a shaftextending in said central opening the outer surface of which is spacedsubstantially from the inner surfaces of said cylinder barrel openingthroughout the maior portion of the axial length of the latter; bearingmeans in said housing carrying said shaft for rotation. and a motionpermitting connector means interconnecting said cylinder barrel andshaft including means forming a plurality of splines carried by saidcylinder barrel and extending in the central opening thereof fromadjacent the end thereof remote from said port plate means for adistance of less than one-third the total length of said cylinderbarrel, and means on said shaft forming a plurality of circumferentiallyspaced straight splines extending axially of said shaft and interfttingwith said splines carried by said cylinder barrel and being of greaterlength than the latter. said splines carried by said cylinder barrelhaving a length such that they extend a limited distance on each side ofa plane passing through the centers of generation of the spherodallyshaped ends of said pistons.

9. A fluid pressure energy translating device including means forming acasing; port plate means in said casing; a cylinder barrel disposed insaid casing, said cylinder barrel having outer walls and opposite ends,one of said ends being in sliding engagement with said port plate means,said cylinder barrel otherwise being at all times out of engagement withand unsupported by said casing, means in said cylinder barrel forming acentral opening extending axially therein and about the axis of whichsaid cylinder barrel rotates, and a plurality of cylinders spaced aroundsaid central opening on axes extending generally parallel to the axis ofsaid central opening; pistons disposed for reciprocation in saidcylinders, said pistons having spheroidally shaped ends the centers ofgeneration of which are disposed on the axial centers of said pistonsand cylinders; an inclined thrust member in said casing disposed inengagement with the spheroidally shaped ends of said pistons; a shaftextending in said central opening the outer surface of which is spacedsubstantially from the inner surfaces of said cylinder barrel openingthroughout the major portion of the axial length of the latter; bearingmeans in said housing carrying said shaft for rotation; and motionpermitting connector means interconnecting said cylinder barrel andshaft including means forming a plurality of splines carried by saidcylinder barrel and extending axially of the central opening thereoffrom adjacent the end thereof remote from said port plate means for adistance of less than one-third the total length of said cylinderbarrel, and means on a shaft forming a plurality of circumferentiallyspaced straight splines extending axially of said shaft and interttingwith said splines carried by said cylinder barrel, said splines carriedby said cylinder barrel having a length such that they extend a limiteddistance on each side of a plane passing through the centers ofgeneration of the spheroidally shaped ends of said pistons.

I0. A fluid pressure energy translating device including means forming acasing; port plate means in said casing; a cylinder barrel disposed insaid casing, said cylinder barrel having outer walls and opposite ends,one of said ends being in sliding engagement with said port plate means,said cylinder barrel otherwise being at all times out of engagement withand unsupported by said casing, means in said cylinder barrel forming acentral opening extending axially therein and about the axis of whichsaid cylinder barrel rotates, and a plurality of cylinders spaced aroundsaid central opening on axes extending generally parallel to the axis ofsaid central opening; pistons disposed for reciprocation in saidcylinders, said pistons having spheroidally shaped ends the centers ofgeneration of which are disposed on the axial centers of said pistonsand cylinders; an inclined thrust member in said casing disposed inengagement with the pheroidally shaped ends of said pistons; a shaftextending in said central opening the outer surface of which is spacedsubstantially from the inner surfaces of said cylinder barrel openingthroughout the major portion f the axial length of the latter; bearingmeans in said housing-carrying said shaft for rotation; and a motionpermitting connector means interconnecting said cylinder barrel andshaft including means forming a plurality of splines carried by saidcylinder barrel and extending in the central opening thereof fromadjacent the end thereof remote from said port plate means, and means onsaid shaft forming a plurality of circumferentially spaced straightsplines extending axially of said shaft cooperating with said splinescarried by said cylinder, said cylinder and shaft .splines havingcooperating interconnecting surfaces of substantially less axial lengththan one-third the overall length of said cylinder barrel, and thelength of said cylinder barrel splines being such that they extend alimited distance on each side 0f a plane passing through the centers ofgeneration of the spheroidally shaped ends of said pistons. v

Il. A fluid pressure energy translating device including means forming acasing,- port plate means in said casing.' a cylinder barrel disposed insaid casing, said cylinder barrel having outer walls and opposite ends,one of said ends being in sliding engagement with said port plate means,said cylinder barrel otherwise being at all times out of engagement withand unsupported by said casing, means in said cylinder barrel forming acentral opening extending axially therein and about the axis of whichsaid cylinder barrel rotates, and a plurality of cylinders spaced aroundsaid central opening on axes extending generally parallel to the axis ofsaid central opening;

pistons disposed for recipmcatfon in said cylinders, said pistons havingspheroidaliy shaped ends the centers of generation of which are disposedon the axial centers of said pistons and cylinders; an inclined thrustmember in said easing disposed in engagement with the spheroidailyshaped ends of said pistons; a shaft extending in said central openingthe outer surface of which is spaced substantially from the innersurfaces of said cylinder barrel opening throughout the maior portion ofthe axial length of the latter.' bearing means in said housing carryingsold shaft for rotation; and a motion permitting connector meansinterconnecting said cylinder barrel and shaft in cludlng means forminga plurality of splines carried by said cylinder barrel and extending inthe central opening thereof from adjacent the end thereof remote fromsaid port plate means. and means on said shaft forming a plurality ofcircumferentially spaced straight splines extending axially of saidshaft cooperating with said splines carried by said cylinder, saidcylinder and straight shaft splines having cooperating interconnectingsurfaces of substantially less axial length than one-third the overalllength of said cylinder barrel.

References Clted 1n the 111e of this patent or the original patent.

UNITED STATES PATENTS 924,787 Janney lune 15, 1909 1,263,180 WilliamsApr. 16, 1918 1,539,616 Williams May 26, 1925 1,817,080 Howard Aug. 4,1931 1,820,266 Bilderdeck Aug. 25, 1931 1,840,866 Rayburn et al Ian. 12,1932 1,924,738 Flanders Aug. 29, 1933 1,970,133 Ferris et al Aug. 14,1934 2,071,800 Mock Feb. 23, 1937 2,093,477 Parsons Sept. 21, 19372,096,907 Linderman Oct. 26, 1937 2,107,079 Mentale Feb. 1, 19382,129,828 Dunn Sept. 13, 1938 2,129,886 Syrovy Sept. 13, 1938 2,161,143Doe et al. June 6, 1939 2,241,701 Doe May 13, 1941 2,248,449 Dudley July8, 1941 2,292,125 Ield Ang. 4, 1942 2,299,233 Holer Oct. 20, 19422,300,009 Rose Oct. 27, 1942 2,331,694 Jeffrey Oct. l2, 1943 2,484,337Ferris Oct. 11, 1949 UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION i eme No. 24 ,O48 August 2 1955 Fred .I Wright It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below.

Column 2, line 49, for "oylindrically {cylindrical} Y' read--cylindrical {cyl} nderical] column 3, line '70, for "36 read --35-;column 6, line 68,

For r1 shaft" read --said shaftcolumn 7, line 18, for "pheroidally" read"spheroidal iy T,

Signed and sealed this 13th day of September 1955.

(SEAL) Attest:

KARL H mmh ROBERT c. WATSON Attesbing Officer Qxunissioner of Patents

